Dry grinding terrazzo floor finishing machine

ABSTRACT

The invention relates to a machine for the dry grinding of terrazzo floors and particularly to the utilization of a vacuum cleaner attachment for the collection and control of dust raised during the grinding operation. This dust comprises fine particles ground from the floor, sand used for dressing the grinding stones and small particles worn from the grinding stones. A chamber of the machine in which the grinding stones are disposed has a vacuum pick-up head and the chamber is formed in part by a loose fitting skirt assembly which is resiliently biased in a downwardly direction. A wear shroud forming the lower part of the skirt assembly is biased into firm engagement with the floor and adjustable vent plates are provided for controlling the flow of air through the chamber. The dust collecting assembly for the machine comprises a drum unit mounted on a wheeled cart which is closely coupled to the machine so that the drum unit is within the lateral confines of the handle of the machine.

United States Patent Vinella [451 0ct.3l, 1972 [54] DRY GRINDINGTERRAZZO FLOOR FINISHING MACHINE [22] Filed: Aprll7,1971

[2l] Appl.No.: 132,147

[52] US. Cl ..5l/l77, 51/273 [51] Int. Cl .3241) 23/00, B241) 55/06 [58]Field of Search ..51/l74, 177, 273,170T

[56] References Cited UNITED STATES PATENTS 3,452,486 7/1969 Lombardo eta1. ..51/177 3,124,911 3/1964 Vinella ..51/177 3,102,372 9/1963 Vezner..5l/l77 2,201,420 5/1940 Zschau ..5l/177 FOREIGN PATENTS ORAPPLICATIONS 1,068,145 10/1959 Germany ..51/170T Primary Examiner-JamesL. Jones, Jr. Attorney-Wayne B. Easton [57] ABSTRACT The inventionrelates to a machine for the dry grinding of terrazzo floors andparticularly to the utilization of a vacuum cleaner attachment for thecollection and control of dust raised during the grinding operation.This dust comprises fine particles ground from the floor, sand used fordressing the grinding stones and small particles worn from the grindingstones. A chamber of the machine in which the grinding stones aredisposed has a vacuum pick-up head and the chamber is formed in part bya loose fitting skirt assembly which is resiliently biased in adownwardly direction. A wear shroud forming the lower part of the skirtassembly is biased into firm engagement with the floor and adjustablevent plates are provided for controlling the flow of air through thechamber. The dust collecting assembly for the machine comprises a drumunit mounted on a wheeled cart which is closely coupled to the machineso that the drum unit is within the lateral confines of the handle ofthe machine.

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Frank 1? vinella 47 TOP/UEJ DRY GRINDING TERRAZZO FLOOR FINISHINGMACHINE This invention relates to a machine for the dry grinding ofterrazzo floors and particularly to an improvement relating to theutilization of a vacuum cleaner attachment for the collection andcontrol of dust raised during the grinding operation. This dustcomprises finely ground particles from the floor, sand used for dressingthe grinding stones and small particles worn from the grinding stones.

A main object of the invention is to provide a new and improved terrazzogrinding machine for the dry grinding of terrazzo floors andparticularly a new and improved dust control and collecting system forsuch machines.

Other objects and advantages of the invention will become apparent fromthe following specification, the drawings and appended claims.

In the drawings:

FIG. 1 is a perspective view of a new and improved terrazzo floor drygrinding machine embodying the invention;

FIG. 2 is a perspective view similar to FIG. 1 but shows the vacuumcleaner drum unit removed and the grinding head assembly of the machinein a tilted position which position is normally used to facilitate thereplacing of grinding stones;

FIG. 3 is a front elevational view of the skirt assembly which forms thegrinding stone chamber portion of the grinding head assembly;

FIG. 4 is a fragmentary perspective view showing fastening means for theattachment of the skirt assembly', and

FIG. 5 is a fragmentary perspective view of a rear portion of thegrinding head assembly showing a fitting for a vacuum cleaner hose, thedrum unit cart and the hitch for the cart.

Referring to the drawings, and particularly FIGS. 1 and 2, the terrazzofloor grinding machine consists of three main parts which are amotorized grinding head assembly 5, a two wheeled carriage assembly 6for making mobile or mobilizing the grinding assembly 5, and a dustcollection assembly 7 which includes a vacuum unit 8 and a three wheelcart 9.

The grinding head assembly 5 includes a main frame or casing part 10which is a generally rectangularly shaped member having verticallyextending walls, with rounded corners, forming the sides thereof. Ahorizontally extending plate member 12 is attached to the top of casingpart 10 with a plurality of bolts. A 220 volt electric motor 15 iscentrally mounted on the plate 12 with the shaft thereof (not shown)extending vertically and downwardly into the confines of easing part 10beneath plate 12.

An electrical box 16 is mounted on plate 12, in front of the motor 15,which contains electrical control apparatus for the motor. Anotherelectrical box 18 is mounted on plate 12, behind the motor 15, which isa service box for receiving electrical power from a supply outletthrough a cable 20 having a male connector 21. Power for the motor 15 issupplied through the service box 18. A cable 23 extending from servicebox 18 serves to supply power to the motor of the vacuum unit Adownwardly extending sheet metal skirt or shroud 30 is fixedly attachedwith lugs and screws 31 (see FIG.

2) to the casing part 10. The shroud 30 has outer dimensions which arenominally the same as the inner dimensions of the casing part 10 so thatthe shroud is nested inside member 10. Within the lateral confines orspace defined by shroud 30 are four spiders 32 each of which has acentrally disposed shaft 34 by which the spiders are symmetricallylocated and mounted for rotation about vertical axes. Each spider 32 hasthree radially extending arms or spokes with a grinding stone 36 beingattached to each spider arm.

Within the lateral confines or space defined by casing part 10 is a gearassembly (not shown) which is driven by the motor 15 and functions torotate the spiders 32 about the axes of their shafts 34. The rotation ofthe spiders 32 cause the stories 36 to move in orbital paths relative tothe axes of the spider shafts 34, in a known manner, to effect thegrinding of terrazzo floors. When the machine is in operation the stones36 support the weight of the grinding head assembly 5 which includes theframe 10, the motor 15 and the enclosed gear assembly. By way ofexample, a typical or representative terrazzo grinding machine mighthave each spider 32 support a weight of about I25 pounds and have amotor speed such that the linear speed of each stone 36 is about 1500feet per minute.

With reference to FIGS. 1 to 3 there is illustrated a skirt assembly 39which depends downwardly from the shroud 30 in surrounding relation tothe spider units 32. Skirt assembly 39 includes a rectangularly shapedsheet metal support member 40 which is formed with four verticallyextending wall portions having rounded corners which correspond to therounded corners of shroud 30. A wear shroud 42 made from a sheet stockof wear resistant nylon material surrounds support member 40 and isattached thereto with a plurality of screws 44. Shroud 42 is similar inshape to support member 40 but has a somewhat lesser height. The holesin shroud 42 for the screws 44 are vertically centered whereas tappedholes for screws 44 in support member 40 are located along the loweredge of support member 40. Shroud 42 is illustrated as being formed withfour parts with two of the parts having the reference numerals 42a and42b and the other two parts forming front and rear inlet or vent plates46 and 47 which are not only separately attached to the support member40 but are also adjustable attached thereto such that they can be raisedto desired adjusted positions. The adjustment feature is facilitated bythree spaced apart vertically extending slots 48 in each of the ventplates 46 and 47 and screws 49 which are also threadedly received intapped holes in support member 40.

The skirt assembly 39 is attached to frame member 10 with elongatedbrackets 50 and 51 which are vertically extending and have the lowerends thereof attached with screws 53 to support member 40. The upperends of brackets 50 and 51 have slots 54 which facilitate the attachmentof the skirt assembly 39 to the frame member 10, this being referred tofurther on herein.

Support member 40 has a row of tapped holes for receiving screws 60which holes are spaced above the row of tapped holes which receive thescrews 44. Screws 60 are utilized for attaching a rubber or plasticsealing strip 62 and an articulated four piece metal strap 64 to supportmember 40. The lower part of sealing strip 62 conforms or is fitted tothe peripheral shape of support member 40 while the upper part of thesealing strip 62 extends above and upwardly relative to the upper edgeof support member 40.

Skirt assembly 39 is resiliently biased towards the floor with theutilization of resilient connections provided between brackets 50 and 51and the frame plate member 12. The resilient connection associated withbracket 51, shown in FIG. 4, is identical to the resilient connectionfor bracket 50. The connection includes an L-shaped bracket 66 havingapertured horizontally and vertically extending legs. The verticallyextending leg is adjustable attached to the skirt bracket 51 with ascrew and nut fastener 68. An adjustment screw 70, which threadedlyengages a tapped hole in plate 12, passes through a hole in thehorizontally extending leg of bracket 66. A helical spring 71 isdisposed between the head of screw 70 and the horizontally extending legof bracket 66. With the above described construction the brackets 50 and51, and hence the entire skirt assembly 39, are resiliently biased in adownwardly direction such that the wear shroud 42 is biased into firmengagement with the floor.

Wear shroud 42 is of course subjected to wear during use. When new, andprior to being subjected to wear, the shroud 42 is verticallysymmetrical relative to the screws 44. After the lower edge thereofbecomes worn the two shroud parts 42a and 42b can be taken off, turnedupside down" and reattached so that the other or upper edge thereof mayalso be subjected to wear. The same is true for vent plates 46 and 47.

In FIG. there is shown a fitting 74 which is attached to and extendsfrom the frame member 10. A passage (not shown) extends from the fitting74 to an air inlet head 76 (FIG. 2) mounted interiorly of the chamberdefined and surrounded by the shroud 30 and the skirt assembly 39.

in the grinding of terrazzo floors the grinding operation involves theundesired production of dust which is made up of particles from theterrazzo floor and silica particles worn from the grinding stones 36.The chamber formed by the shroud 30 and the skirt assembly 39 has fluidtight sealing at the top thereof by reason of the upper lip 78 of thesealing strip 62 extending inwardly into sealing engagement with theshroud 30 and fluid tight sealing at the bottom thereof (except for thevent plates 46 and 47) by reason of the wear shroud 42 (parts 420 and42b) being resiliently biased downwardly into engagement with the floor.

The grinding head assembly 5, which includes casing part and motor 15,is made mobile for use in grinding floors with the two wheeled carriage6 which comprises a chassis frame which supports an axle 80 to whichwheels 82 are rotatably mounted. Carriage 6 includes two spaced apart,forwardly extending arms 84, the forward ends of which have pivotalconnections with the casing part 10. These pivotal connection pointshaving a common horizontal axis which is through the center of gravityof the grinding head assembly S. A rectangularly shaped handle 86 isfixedly attached to the chassis frame of carriage 6 for facilitating andcontrolling the movement of the grinding head assembly 5 in the floorgrinding operations.

The wheeled cart 9 comprises a generally circularly shaped frame member92 having three wheels 94 in spaced relation to each other. A detachablehitch 96 is provided between the cart 9 and carriage 6 so that the cart9 functions as a trailer relative to the carriage 6. Frame 92 has crosspieces 98 for supporting the cylindrically shaped vacuum drum unit 8.Vacuum drum unit 8 has incorporated therein an electric motor 100 andsuction fan unit (not shown) and a conventional suction hose 102 extendsfrom the upper part of unit 8 to the fitting 74 on casing part 10 towhich it is detachable connectable. An electric cord 104 extends fromthe motor 100 and is shown connected to the electric cord 23 whichextends from the service box 18. Fitting 74 provides fluid communicationbetween the hose 102 and the interior space defined by the shroud 30 andthe skirt assembly 39. The vacuum pick-up unit or head 76 disposed inthis interior space has fluid communication with the vacuum unit 8through the fitting 74 and the hose 102.

Carriage assembly 6 has a bracket immediately above the wheel portion 72thereof for holding a counterbalancing weight 112. During the floorgrinding operations the entire weight of the grinding head assembly 5 issupported on or by the grinding stones 36. When it is desired to replaceworn stones the dust collection assembly 7 may be detached or removed bythe disconnecting of cart 9 from the carriage 6, disconnecting hose 102from the fitting 74, disconnecting the electrical cord 104 from theelectrical cord 23, lifting the drum unit 8 from between the confines ofhandle 86, and pivoting the machine about the axis of the wheels 82 asshown in FIG. 2. The weight 112 is moved to the upper part of the handle86 to hold the machine in the pivoted position of FIG. 2 and, with themachine in this position, the grinding stones 36 may be replaced.

On the other hand, the machine may be designed so that the head assembly5 may be tilted back as illustrated in FIG. 2 without disconnecting thecart 9 from the carriage 6. In that case it would also not be necessaryto make the other disconnections referred to above such as the hose 102from the fitting 74, the cord 104 from the cord 23, or lifting the drumfrom the confines of handle 86. It might be desirable to remove the hose102 as a matter of prudence, however, so as to avoid accidentalstressing or damage.

1 claim:

1. A terrazzo floor grinding machine comprising a generallyrectangularly shaped support structure, a plurality of grinding stonecarriers rotatably mounted on the underside of said support structure,said support structure having smoothly merging lower sidewalls, agenerally rectangularly shaped skirt assembly forming a chamber beneaththe underside of said support member, said skirt assembly having itsupper portion formed with a sealing member and its lower portion formedwith a shroud wear member, said sealing member having a lip in sealingengagement with said support structure lower sidewalls, means forapplying a vacuum to said chamber, and adjustable vent means forcontrolling the degree of vacuum applied to said chamber.

2. A machine according to claim 1 wherein said skirt assembly includes agenerally rectangularly shaped support member, said sealing member beingattached to said support member, said shroud wear members beingreversibly attached to said support member so plate being verticallyadjustable for adjusting the venting of air into said chamber.

5. A machine according to claim 1 including a carriage having two wheelsand a pair of forwardly extending arms attached to said supportstructure, said carriage having a rearwardly inclined rectangularlyshaped handle, a wheeled cart attached to said carriage, a drum shapedvacuum cleaner unit mounted on said cart and within the lateral confinesof said handle.

1. A terrazzo floor grinding machine comprising a generallyrectangularly shaped support structure, a plurality of grinding stonecarriers rotatably mounted on the underside of said support structure,said support structure having smoothly merging lower sidewalls, agenerally rectangularly shaped skirt assembly forming a chamber beneaththe underside of said support member, said skirt assembly having itsupper portion formed with a sealing member and its lower portion formedwith a shroud wear member, said sealing member having a lip in sealingengagement with said support structure lower sidewalls, means forapplying a vacuum to said chamber, and adjustable vent means forcontrolling the degree of vacuum applied to said chamber.
 2. A machineaccording to claim 1 wherein said skirt assembly includes a generallyrectangularly shaped support member, said sealing member being attachedto said support member, said shroud wear members being reversiblyattached to said support member so that the upper and lower edgesthereof may be used as wearing edges.
 3. A machine according to claim 1including vertically extending brackets attached to said skirt assembly,and resilient means between said brackets and said support structure forresiliently biasing said skirt assembly towards the floor.
 4. A machineaccording to claim 2 wherein two of said shroud wear members are spacedapart, a vent plate disposed between said two wear members, said platebeing vertically adjustable for adjusting the venting of air into saidchamber.
 5. A machine according to claim 1 including a carriage havingtwo wheels and a pair of forwardly extending arms attached to saidsupport structure, said carriage having a rearwardly inclinedrectangularly shaped handle, a wheeled cart attached to said carriage, adrum shaped vacuum cleaner unit mounted on said cart and within thelateral confines of said handle.